crypto/property/property.c

   1 /*
   2  * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
   4  *
   5  * Licensed under the Apache License 2.0 (the "License").  You may not use
   6  * this file except in compliance with the License.  You can obtain a copy
   7  * in the file LICENSE in the source distribution or at
   8  * https://www.openssl.org/source/license.html
   9  */
  10
  11 #include <string.h>
  12 #include <stdio.h>
  13 #include <stdarg.h>
  14 #include <openssl/crypto.h>
  15 #include "internal/property.h"
  16 #include "internal/ctype.h"
  17 #include <openssl/lhash.h>
  18 #include <openssl/rand.h>
  19 #include "internal/thread_once.h"
  20 #include "internal/lhash.h"
  21 #include "internal/sparse_array.h"
  22 #include "property_lcl.h"
  23
  24 /* The number of elements in the query cache before we initiate a flush */
  25 #define IMPL_CACHE_FLUSH_THRESHOLD  500
  26
  27 typedef struct {
  28     const OSSL_PROVIDER *provider;
  29     OSSL_PROPERTY_LIST *properties;
  30     void *method;
  31     void (*method_destruct)(void *);
  32 } IMPLEMENTATION;
  33
  34 DEFINE_STACK_OF(IMPLEMENTATION)
  35
  36 typedef struct {
  37     const char *query;
  38     void *method;
  39     char body[1];
  40 } QUERY;
  41
  42 DEFINE_LHASH_OF(QUERY);
  43
  44 typedef struct {
  45     int nid;
  46     STACK_OF(IMPLEMENTATION) *impls;
  47     LHASH_OF(QUERY) *cache;
  48 } ALGORITHM;
  49
  50 struct ossl_method_store_st {
  51     OPENSSL_CTX *ctx;
  52     size_t nelem;
  53     SPARSE_ARRAY_OF(ALGORITHM) *algs;
  54     OSSL_PROPERTY_LIST *global_properties;
  55     int need_flush;
  56     unsigned int nbits;
  57     unsigned char rand_bits[(IMPL_CACHE_FLUSH_THRESHOLD + 7) / 8];
  58     CRYPTO_RWLOCK *lock;
  59 };
  60
  61 typedef struct {
  62     LHASH_OF(QUERY) *cache;
  63     size_t nelem;
  64     uint32_t seed;
  65 } IMPL_CACHE_FLUSH;
  66
  67 DEFINE_SPARSE_ARRAY_OF(ALGORITHM);
  68
  69 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid);
  70 static void ossl_method_cache_flush_all(OSSL_METHOD_STORE *c);
  71
  72 int ossl_property_read_lock(OSSL_METHOD_STORE *p)
  73 {
  74     return p != NULL ? CRYPTO_THREAD_read_lock(p->lock) : 0;
  75 }
  76
  77 int ossl_property_write_lock(OSSL_METHOD_STORE *p)
  78 {
  79     return p != NULL ? CRYPTO_THREAD_write_lock(p->lock) : 0;
  80 }
  81
  82 int ossl_property_unlock(OSSL_METHOD_STORE *p)
  83 {
  84     return p != 0 ? CRYPTO_THREAD_unlock(p->lock) : 0;
  85 }
  86
  87 static openssl_ctx_run_once_fn do_method_store_init;
  88 int do_method_store_init(OPENSSL_CTX *ctx)
  89 {
  90     return ossl_property_parse_init(ctx);
  91 }
  92
  93 static unsigned long query_hash(const QUERY *a)
  94 {
  95     return OPENSSL_LH_strhash(a->query);
  96 }
  97
  98 static int query_cmp(const QUERY *a, const QUERY *b)
  99 {
 100     return strcmp(a->query, b->query);
 101 }
 102
 103 static void impl_free(IMPLEMENTATION *impl)
 104 {
 105     if (impl != NULL) {
 106         if (impl->method_destruct)
 107             impl->method_destruct(impl->method);
 108         OPENSSL_free(impl);
 109     }
 110 }
 111
 112 static void impl_cache_free(QUERY *elem)
 113 {
 114     OPENSSL_free(elem);
 115 }
 116
 117 static void alg_cleanup(ossl_uintmax_t idx, ALGORITHM *a)
 118 {
 119     if (a != NULL) {
 120         sk_IMPLEMENTATION_pop_free(a->impls, &impl_free);
 121         lh_QUERY_doall(a->cache, &impl_cache_free);
 122         lh_QUERY_free(a->cache);
 123         OPENSSL_free(a);
 124     }
 125 }
 126
 127 /*
 128  * The OPENSSL_CTX param here allows access to underlying property data needed
 129  * for computation
 130  */
 131 OSSL_METHOD_STORE *ossl_method_store_new(OPENSSL_CTX *ctx)
 132 {
 133     OSSL_METHOD_STORE *res;
 134
 135     if (!openssl_ctx_run_once(ctx,
 136                               OPENSSL_CTX_METHOD_STORE_RUN_ONCE_INDEX,
 137                               do_method_store_init))
 138         return NULL;
 139
 140     res = OPENSSL_zalloc(sizeof(*res));
 141     if (res != NULL) {
 142         res->ctx = ctx;
 143         if ((res->algs = ossl_sa_ALGORITHM_new()) == NULL) {
 144             OPENSSL_free(res);
 145             return NULL;
 146         }
 147         if ((res->lock = CRYPTO_THREAD_lock_new()) == NULL) {
 148             OPENSSL_free(res->algs);
 149             OPENSSL_free(res);
 150             return NULL;
 151         }
 152     }
 153     return res;
 154 }
 155
 156 void ossl_method_store_free(OSSL_METHOD_STORE *store)
 157 {
 158     if (store != NULL) {
 159         ossl_sa_ALGORITHM_doall(store->algs, &alg_cleanup);
 160         ossl_sa_ALGORITHM_free(store->algs);
 161         ossl_property_free(store->global_properties);
 162         CRYPTO_THREAD_lock_free(store->lock);
 163         OPENSSL_free(store);
 164     }
 165 }
 166
 167 static ALGORITHM *ossl_method_store_retrieve(OSSL_METHOD_STORE *store, int nid)
 168 {
 169     return ossl_sa_ALGORITHM_get(store->algs, nid);
 170 }
 171
 172 static int ossl_method_store_insert(OSSL_METHOD_STORE *store, ALGORITHM *alg)
 173 {
 174         return ossl_sa_ALGORITHM_set(store->algs, alg->nid, alg);
 175 }
 176
 177 int ossl_method_store_add(OSSL_METHOD_STORE *store, const OSSL_PROVIDER *prov,
 178                           int nid, const char *properties, void *method,
 179                           int (*method_up_ref)(void *),
 180                           void (*method_destruct)(void *))
 181 {
 182     ALGORITHM *alg = NULL;
 183     IMPLEMENTATION *impl;
 184     int ret = 0;
 185     int i;
 186
 187     if (nid <= 0 || method == NULL || store == NULL)
 188         return 0;
 189     if (properties == NULL)
 190         properties = "";
 191
 192     /* Create new entry */
 193     impl = OPENSSL_malloc(sizeof(*impl));
 194     if (impl == NULL)
 195         return 0;
 196     if (method_up_ref != NULL && !method_up_ref(method)) {
 197         OPENSSL_free(impl);
 198         return 0;
 199     }
 200     impl->provider = prov;
 201     impl->method = method;
 202     impl->method_destruct = method_destruct;
 203
 204     /*
 205      * Insert into the hash table if required.
 206      *
 207      * A write lock is used unconditionally because we wend our way down to the
 208      * property string code which isn't locking friendly.
 209      */
 210     ossl_property_write_lock(store);
 211     ossl_method_cache_flush(store, nid);
 212     if ((impl->properties = ossl_prop_defn_get(store->ctx, properties)) == NULL) {
 213         impl->properties = ossl_parse_property(store->ctx, properties);
 214         if (impl->properties == NULL)
 215             goto err;
 216         ossl_prop_defn_set(store->ctx, properties, impl->properties);
 217     }
 218
 219     alg = ossl_method_store_retrieve(store, nid);
 220     if (alg == NULL) {
 221         if ((alg = OPENSSL_zalloc(sizeof(*alg))) == NULL
 222                 || (alg->impls = sk_IMPLEMENTATION_new_null()) == NULL
 223                 || (alg->cache = lh_QUERY_new(&query_hash, &query_cmp)) == NULL)
 224             goto err;
 225         alg->nid = nid;
 226         if (!ossl_method_store_insert(store, alg))
 227             goto err;
 228     }
 229
 230     /* Push onto stack if there isn't one there already */
 231     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
 232         const IMPLEMENTATION *tmpimpl = sk_IMPLEMENTATION_value(alg->impls, i);
 233
 234         if (tmpimpl->provider == impl->provider
 235             && tmpimpl->properties == impl->properties)
 236             break;
 237     }
 238     if (i == sk_IMPLEMENTATION_num(alg->impls)
 239         && sk_IMPLEMENTATION_push(alg->impls, impl))
 240         ret = 1;
 241     ossl_property_unlock(store);
 242     if (ret == 0)
 243         impl_free(impl);
 244     return ret;
 245
 246 err:
 247     ossl_property_unlock(store);
 248     alg_cleanup(0, alg);
 249     impl_free(impl);
 250     return 0;
 251 }
 252
 253 int ossl_method_store_remove(OSSL_METHOD_STORE *store, int nid,
 254                              const void *method)
 255 {
 256     ALGORITHM *alg = NULL;
 257     int i;
 258
 259     if (nid <= 0 || method == NULL || store == NULL)
 260         return 0;
 261
 262     ossl_property_write_lock(store);
 263     ossl_method_cache_flush(store, nid);
 264     alg = ossl_method_store_retrieve(store, nid);
 265     if (alg == NULL) {
 266         ossl_property_unlock(store);
 267         return 0;
 268     }
 269
 270     /*
 271      * A sorting find then a delete could be faster but these stacks should be
 272      * relatively small, so we avoid the overhead.  Sorting could also surprise
 273      * users when result orderings change (even though they are not guaranteed).
 274      */
 275     for (i = 0; i < sk_IMPLEMENTATION_num(alg->impls); i++) {
 276         IMPLEMENTATION *impl = sk_IMPLEMENTATION_value(alg->impls, i);
 277
 278         if (impl->method == method) {
 279             sk_IMPLEMENTATION_delete(alg->impls, i);
 280             ossl_property_unlock(store);
 281             impl_free(impl);
 282             return 1;
 283         }
 284     }
 285     ossl_property_unlock(store);
 286     return 0;
 287 }
 288
 289 int ossl_method_store_fetch(OSSL_METHOD_STORE *store, int nid,
 290                             const char *prop_query, void **method)
 291 {
 292     ALGORITHM *alg;
 293     IMPLEMENTATION *impl;
 294     OSSL_PROPERTY_LIST *pq = NULL, *p2;
 295     int ret = 0;
 296     int j, best = -1, score, optional;
 297
 298 #ifndef FIPS_MODE
 299     OPENSSL_init_crypto(OPENSSL_INIT_LOAD_CONFIG, NULL);
 300 #endif
 301
 302     if (nid <= 0 || method == NULL || store == NULL)
 303         return 0;
 304
 305     /*
 306      * This only needs to be a read lock, because queries never create property
 307      * names or value and thus don't modify any of the property string layer.
 308      */
 309     ossl_property_read_lock(store);
 310     alg = ossl_method_store_retrieve(store, nid);
 311     if (alg == NULL) {
 312         ossl_property_unlock(store);
 313         return 0;
 314     }
 315
 316     if (prop_query == NULL) {
 317         if ((impl = sk_IMPLEMENTATION_value(alg->impls, 0)) != NULL) {
 318             *method = impl->method;
 319             ret = 1;
 320         }
 321         goto fin;
 322     }
 323     pq = ossl_parse_query(store->ctx, prop_query);
 324     if (pq == NULL)
 325         goto fin;
 326     if (store->global_properties != NULL) {
 327         p2 = ossl_property_merge(pq, store->global_properties);
 328         if (p2 == NULL)
 329             goto fin;
 330         ossl_property_free(pq);
 331         pq = p2;
 332     }
 333     optional = ossl_property_has_optional(pq);
 334     for (j = 0; j < sk_IMPLEMENTATION_num(alg->impls); j++) {
 335         impl = sk_IMPLEMENTATION_value(alg->impls, j);
 336         score = ossl_property_match_count(pq, impl->properties);
 337         if (score > best) {
 338             *method = impl->method;
 339             ret = 1;
 340             if (!optional)
 341                 goto fin;
 342             best = score;
 343         }
 344     }
 345 fin:
 346     ossl_property_unlock(store);
 347     ossl_property_free(pq);
 348     return ret;
 349 }
 350
 351 int ossl_method_store_set_global_properties(OSSL_METHOD_STORE *store,
 352                                             const char *prop_query) {
 353     int ret = 0;
 354
 355     if (store == NULL)
 356         return 1;
 357
 358     ossl_property_write_lock(store);
 359     ossl_method_cache_flush_all(store);
 360     if (prop_query == NULL) {
 361         ossl_property_free(store->global_properties);
 362         store->global_properties = NULL;
 363         ossl_property_unlock(store);
 364         return 1;
 365     }
 366     store->global_properties = ossl_parse_query(store->ctx, prop_query);
 367     ret = store->global_properties != NULL;
 368     ossl_property_unlock(store);
 369     return ret;
 370 }
 371
 372 static void impl_cache_flush_alg(ossl_uintmax_t idx, ALGORITHM *alg)
 373 {
 374     lh_QUERY_doall(alg->cache, &impl_cache_free);
 375     lh_QUERY_flush(alg->cache);
 376 }
 377
 378 static void ossl_method_cache_flush(OSSL_METHOD_STORE *store, int nid)
 379 {
 380     ALGORITHM *alg = ossl_method_store_retrieve(store, nid);
 381
 382     if (alg != NULL) {
 383         store->nelem -= lh_QUERY_num_items(alg->cache);
 384         impl_cache_flush_alg(0, alg);
 385     }
 386 }
 387
 388 static void ossl_method_cache_flush_all(OSSL_METHOD_STORE *store)
 389 {
 390     ossl_sa_ALGORITHM_doall(store->algs, &impl_cache_flush_alg);
 391     store->nelem = 0;
 392 }
 393
 394 IMPLEMENT_LHASH_DOALL_ARG(QUERY, IMPL_CACHE_FLUSH);
 395
 396 /*
 397  * Flush an element from the query cache (perhaps).
 398  *
 399  * In order to avoid taking a write lock or using atomic operations
 400  * to keep accurate least recently used (LRU) or least frequently used
 401  * (LFU) information, the procedure used here is to stochastically
 402  * flush approximately half the cache.
 403  *
 404  * This procedure isn't ideal, LRU or LFU would be better.  However,
 405  * in normal operation, reaching a full cache would be unexpected.
 406  * It means that no steady state of algorithm queries has been reached.
 407  * That is, it is most likely an attack of some form.  A suboptimal clearance
 408  * strategy that doesn't degrade performance of the normal case is
 409  * preferable to a more refined approach that imposes a performance
 410  * impact.
 411  */
 412 static void impl_cache_flush_cache(QUERY *c, IMPL_CACHE_FLUSH *state)
 413 {
 414     uint32_t n;
 415
 416     /*
 417      * Implement the 32 bit xorshift as suggested by George Marsaglia in:
 418      *      https://doi.org/10.18637/jss.v008.i14
 419      *
 420      * This is a very fast PRNG so there is no need to extract bits one at a
 421      * time and use the entire value each time.
 422      */
 423     n = state->seed;
 424     n ^= n << 13;
 425     n ^= n >> 17;
 426     n ^= n << 5;
 427     state->seed = n;
 428
 429     if ((n & 1) != 0)
 430         OPENSSL_free(lh_QUERY_delete(state->cache, c));
 431     else
 432         state->nelem++;
 433 }
 434
 435 static void impl_cache_flush_one_alg(ossl_uintmax_t idx, ALGORITHM *alg,
 436                                      void *v)
 437 {
 438     IMPL_CACHE_FLUSH *state = (IMPL_CACHE_FLUSH *)v;
 439
 440     state->cache = alg->cache;
 441     lh_QUERY_doall_IMPL_CACHE_FLUSH(state->cache, &impl_cache_flush_cache,
 442                                     state);
 443 }
 444
 445 static void ossl_method_cache_flush_some(OSSL_METHOD_STORE *store)
 446 {
 447     IMPL_CACHE_FLUSH state;
 448
 449     state.nelem = 0;
 450     if ((state.seed = OPENSSL_rdtsc()) == 0)
 451         state.seed = 1;
 452     store->need_flush = 0;
 453     ossl_sa_ALGORITHM_doall_arg(store->algs, &impl_cache_flush_one_alg, &state);
 454     store->nelem = state.nelem;
 455 }
 456
 457 int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, int nid,
 458                                 const char *prop_query, void **method)
 459 {
 460     ALGORITHM *alg;
 461     QUERY elem, *r;
 462
 463     if (nid <= 0 || store == NULL)
 464         return 0;
 465
 466     ossl_property_read_lock(store);
 467     alg = ossl_method_store_retrieve(store, nid);
 468     if (alg == NULL) {
 469         ossl_property_unlock(store);
 470         return 0;
 471     }
 472
 473     elem.query = prop_query != NULL ? prop_query : "";
 474     r = lh_QUERY_retrieve(alg->cache, &elem);
 475     if (r == NULL) {
 476         ossl_property_unlock(store);
 477         return 0;
 478     }
 479     *method = r->method;
 480     ossl_property_unlock(store);
 481     return 1;
 482 }
 483
 484 int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, int nid,
 485                                 const char *prop_query, void *method)
 486 {
 487     QUERY elem, *old, *p = NULL;
 488     ALGORITHM *alg;
 489     size_t len;
 490
 491     if (nid <= 0 || store == NULL)
 492         return 0;
 493     if (prop_query == NULL)
 494         return 1;
 495
 496     ossl_property_write_lock(store);
 497     if (store->need_flush)
 498         ossl_method_cache_flush_some(store);
 499     alg = ossl_method_store_retrieve(store, nid);
 500     if (alg == NULL) {
 501         ossl_property_unlock(store);
 502         return 0;
 503     }
 504
 505     if (method == NULL) {
 506         elem.query = prop_query;
 507         if (lh_QUERY_delete(alg->cache, &elem) != NULL)
 508             store->nelem--;
 509         ossl_property_unlock(store);
 510         return 1;
 511     }
 512     p = OPENSSL_malloc(sizeof(*p) + (len = strlen(prop_query)));
 513     if (p != NULL) {
 514         p->query = p->body;
 515         p->method = method;
 516         memcpy((char *)p->query, prop_query, len + 1);
 517         if ((old = lh_QUERY_insert(alg->cache, p)) != NULL) {
 518             OPENSSL_free(old);
 519             ossl_property_unlock(store);
 520             return 1;
 521         }
 522         if (!lh_QUERY_error(alg->cache)) {
 523             if (++store->nelem >= IMPL_CACHE_FLUSH_THRESHOLD)
 524                 store->need_flush = 1;
 525             ossl_property_unlock(store);
 526             return 1;
 527         }
 528     }
 529     ossl_property_unlock(store);
 530     OPENSSL_free(p);
 531     return 0;
 532 }